All types of vehicles having enclosed passenger compartments, including automobiles, trucks, vans and mini-vans, continue to grow in popularity with the number of these vehicles predicted to increase in the future. Vehicle manufacturers, recognizing this ever-growing market, are continually striving to improve their products. These improvements include on board computers for regulating and monitoring engine performance, improved aerodynamic design for better gas mileage and aesthetic appearance, interior upholstery which rivals that found in the living rooms of many homes, and even computers which calculate and display by LEDs on the dashboard everything from gas mileage to the preferred route for a trip. Despite such advances, manufacturers have been unable to satisfactorily solve the problem of forward firewall or bulkhead doors which improperly open and close upon manual adjustment of control levers for regulating the environment in the passenger compartment.
Most vehicles have a control module mounted in the dashboard for regulating the temperature within the passenger compartment. Other functions such as venting and defrosting of the vehicle windows also are controlled by manual adjustment of the module levers. The levers are connected by cables to the bulkhead doors which are movably mounted for opening and closing apertures formed in the bulkhead.
For example, in many automobiles one of the levers of the control module is moved to the "hot" position for opening a door on the bulkhead and permitting heat to be blown into the passenger compartment during cold weather. As the lever is moved from the "cold" to "hot" position, tension is caused in the cable extending between the lever and door, and the door is pulled to the open position. When the lever is returned to the "cold" position, the tension in the cable is relieved and the door closes.
Problems occur because the cable is slideably mounted in a casing which typically follows a circuitous path between the control module and door. The casing is required for maintaining the integrity of the cable. In most vehicles, the cable casing is mounted at its ends adjacent the door and control module lever, and when the cable is tensioned the casing ends are forced against their mounting members if any excess slack is present in the casing. This excess slack cannot be relieved because the casing ends are immovable. Thus, the cable follows the circuitous path of the casing and because of this excess slack, the cable does not achieve the proper tension required for opening the bulkhead door. Also, possible failure of the mounting members for the casing ends is increased due to the pressure exerted on the casing ends by the compressed casing. A similar problem occurs when an attempt is made to close the door, in that adequate displacement of the cable toward the door is not achieved because the cable again follows the circuitous path of the excessively slackened casing.
Therefore it is apparent that excess slack in the cable casing prevents proper environment control within the vehicle passenger compartment. The operator of the vehicle often is confused because the expected position of the bulkhead door is not achieved when the control module lever is adjusted. Thus, although the lever may be positioned at full "hot", which indicates that the door is completely open, the actual position of the door may indeed only be half open.
The present invention satisfactorily solves the above-described problems and is economical to manufacture and install on a vehicle. More particularly, a worker on an assembly line can install the assembly on a vehicle and adjust the casing to remove the excess slack therefrom in a short amount of time and without delaying the assembly line timetable.
The phenomenon of excess slack in a casing for a cable extending between two movable members occurs in applications other than the one described above. For example, the same problems are common in the cable casing which extends between the control lever and the throttle of a lawn mower engine.
Attempts to solve such problems are well-known in the art and include such prior art devices as a turnbuckle connected to the cable casing, the mounting of a spring clip on the door end of the cable which is operatively connected to the control lever, and the use of a Bowden wire. However, many of these prior art devices require time-consuming installation and manual adjustment.
Known prior art assemblies include quick-connect fittings of the type used with pneumatic and hydraulic pressure system tubing and the like, and instant push-in tube fittings of the type which comprise a main lightweight body, an O-ring fluid seal and a plastic collet having stainless steel teeth.
There is no assembly for the self-adjustment of a cable casing of which I am aware other than my present invention, which is quickly and easily installed and adjusted on a vehicle on a production line at a vehicle manufacturing plant, which will provide for the continuous removal of excess slack in a cable casing even after the vehicle leaves the factory and during certain routine operations of the movable members to which the cable is attached, and which is rugged and relatively inexpensive to manufacture and install.